Rain Water Harvesting- Introduction
Rain water harvesting promotes conservation of water by using few techniques and practices. It will accommodate future shortage of water. Many developed countries are successfully implementing this technique. They are giving countless benefits to their country, people and environment. Rain water harvesting works efficiently in those areas where overall percentage of rainfall is high. People living in such areas can convert disaster into opportunity by organizing a convenient setup of collecting water while raining.
After 19th century, human population progressively increasing. Particularly between 2015 to 2020 there was abrupt rise in human population. Due to medical convenience diseases started to cure completely or partially. Similarly, a common practicing of biotechnology played well to vanish food insecurities. All such facilities overshadowed the rate of mortality in society leading over population.
Due to over population, vital need of people start diminishing day by day. Water is required not only for daily use but it should stored for future generations. Unfortunately, developing nations are in strenuous situation to crack this hurdle. Despite of this reality people are not understanding nevertheless.
Water Crises in Pakistan
Due to economic instability, shortage of water in Pakistan reaches to an alarming level. Inaccessibility to clean water is now current issue in a country. Agencies, NGO’s, Governmental organization are not paying good attention to this vast problem due to lack of funds and finances. Water management must be given top priority, and money must be invested in water infrastructure. The capacity of water storage must be increased, irrigation systems must be improved, and water conservation methods must be promoted.
Primary Causes of Water Shortage in Pakistan
The problem is too burdensome to handle successfully. We should change our behavior regarding usage of water with this view that this natural resource will going to deplete soon. There are various primary causes behind the rise of this situation.
- Climate change.
Climate is now changing worldwide. Uncontrolled human activities create changing in overall chemistry of environment. System is now fail to respond to numerous natural calamities and are clearly malfunctioning. Lack of managerial activities further augment this problem. The country already faces risks to its water resources from the effects of climate change, as seen by changes in monsoon patterns, retreating glaciers, rising temperatures, and recurrent floods and droughts. In the recent years, Pakistan has had numerous floods as well as protracted droughts.
- Rapid population growth.
Mismanagement, improper check and balance, female education deficit, falling mortality rate, degradation of environment are the leading reasons behind rapid population growth. Government should issue relevant rules and regulations regarding family planning. Awareness campaigns should work actively to elevate the realization. High rates of population increase in Pakistan are associated with misery, ignorance, a low level of living, lack of wealth, and a cycle of poverty.
- Mismanagement of water resources.
Pakistan is now in debt. It needs immediate financial assistance for dams construction. Constructed dams are not enough to manage water specially during monsoon season. Due to this, every year flash floods invade Pakistan. This constant disaster weakens the strength of Pakistan to deal with it every year. This disaster can turn into opportunity if experts, officials act wisely and properly. Large-scale water waste is a result of the deteriorating water infrastructure. One of the world’s least effective irrigation systems is found in this nation. While being transported through canals and distributaries, the remaining water is lost. Rain water harvesting plays vital role to favor water conservation.
Secondary Causes of Water Shortage in Pakistan
Along with major primary causes discussed above, there are some secondary causes as well. These causes actually branched from primary causes to further elevate this crises.
Water pollution is the deterioration of water bodies(lakes, rivers, ponds, streams, canals, drainage, dams .etc). It is the either intentional or unintentional act of human beings by throwing garbage, toxic substances directly into water bodies. Due to addition of foreign materials, chemistry of water start changing which is detrimental for marine life. Present situation of water pollution in Pakistan is chaotic. In Pakistan, microbial pollution has been discovered as one of the serious problems in rural as well as urban areas. This is due to the leakage of pipe, pollution from sewage lines intrusion into drinking water supplies, and so forth. Drinking water sources, both surface and groundwater are contaminated
with coliforms, toxic metals and pesticides throughout the country. Water pollution are of various types depending upon the source of water which is polluting:
- Surface water pollution.
- Ground water pollution.
- Microbiological pollution.
- Oxygen depletion pollution.
Unplanned urban growth is described as the occurrence of informal settlements that lack essential infrastructure and services and that contribute to the hazard-creation process because there are no planning criteria or organizing urban rules. Improper urban planning is the prominent reason of water shortage. People highly indulge themselves in constructing housing societies, commercial areas, amusement parks. Due to extreme construction, ground water start depleting. In Pakistan people usually bore their land for easy access of water.
They are still unaware about ground water depletion in Pakistan, they freely use fresh and clean water for their car wash, car porch wash, floor cleaning. Additionally, unplanned urban growth has made communicable diseases—including those that are food- and water-borne—worse. Diseases like tuberculosis flourish in crowded settings and are made worse by dirty surroundings. Urban buildings can easily practice rain water harvesting at rooftops.
Overuse of groundwater.
Ground water is the natural reservoir. It should be use when the capacity of surface water is not fulfilling human and wildlife needs. Uncontrolled anthropogenic activities compelled them to use ground water to meet their needs. Educational institutions, Governmental organizations, NGOs and Volunteer teams can play their role to raise awareness among public regarding ground water recharge methods. Following methods can easily compensate overuse of ground water:
- Spreading basins.
- Recharge pits.
- Recharge wells.
- Subsurface dams.
- Farm ponds.
- Check dams in rainy season.
Low water productivity.
The amount of yield per unit of water utilized is referred to as water productivity. In order to assure that water will be available in the future to fulfill the rising need for food, fiber, and other uses as well as other purposes, water must first be released from its current low productivity usage. This will also lessen the likelihood of conflict. For companies or services where the cost of water as an input or contamination of water through use is of major concern, efforts to reduce water withdrawals can be highly important.
Focusing solely on water withdrawals, however, may provide an inaccurate picture of changes in freshwater depletion and the danger of water shortages that go along with it. Instead than relying on water withdrawal, our estimates of water productivity should be based on consumptive water consumption. Water productivity could easily improved through rain water harvesting.
Components for Installing Rain Water Harvesting System
For the successful installation of rain water harvesting system following components are required. The overall working of this system highly depends upon the efficiency and functionality of these components.
The catchment area is where precipitation first comes into touch.
The impurities that may be on the roof are more significant than the roof’s material. Avoiding lead-containing metal flashing or wood shingles is crucial in all circumstances. The slope of the roof influences the speed of water runoff during a rain event.
A steep roof will swiftly shed runoff and make it easier to remove contaminants from the roof. Since the water will travel more slowly on a flatter, less inclined roof, there is higher probability that contamination may stay on the catchment surface.
The amount of rainwater you may collect will depend on the size of the catchment area or roof. The area is determined by the “footprint” of the roof, which may be computed by adding the area of the overhanging roof to the area of the building.
The pretentious name for the gutters and downspouts is the conveyance system. In essence, these are the pipe networks that transport water from the surface of the roof to the storage containers. However, Poly vinyl chloride piping is most frequently advised for use in rain water harvesting while transporting water. You can paint the PVC pipes to match the color of the building to improve the appearance.
The part of a rain water harvesting system that is most obvious or recognizable is frequently the storage container. It is the location where rainwater collection systems direct and store water for later use. Safety is the storage tank’s primary objective. It must be secure so that both children and animals cannot reach the tank, and it must store water that is fit for human consumption.
Rainwater is purified to make it safe for consumption. To better assist you in understanding the care and handling of rainwater, this material has been separated into three parts.
Roof water Quality, the first portion, goes over possible contaminants in rainwater and describes what we’re aiming to remediate for.
Pre-storage treatment, which makes the water cleaner before it enters the storage tank, is covered in the second section.
The after-storage treatment, which cleans and purifies the water so that it can be used safely, will be covered in the last parts.
All of the pipelines, pumps, and other equipment that transport water from the storage and treatment to the point of use are considered to be part of a rain water harvesting distribution system.
Pros and Cons of Rain Water Harvesting System.
Pros of RWH.
- When water is needed, rainwater harvesting offers a supply of it. It is controlled and administered by the owner.
- It offers a crucial reserve in emergency situations and/or when public water delivery systems fail, especially after natural catastrophes.
- Rooftop rainwater catchment systems are easy to build, and local people can be quickly educated to do so, lowering the overall cost.
- Technology is adaptable. Almost every requirement can be met by the systems. Families in need can begin with a single small tank and add additional as they become able to.
- When cisterns are erected as part of the substructure of the buildings, as is the case with required cisterns, it can improve the engineering of building foundations.
- Rainwater may have better physical and chemical characteristics than groundwater or surface waters that may have experienced pollution, often from unidentified sources.
- Running expenses are minimal.
- Construction, operation, and maintenance don’t require a lot of manpower.
Cons of RWH.
- Rain water harvesting depends on how often and how much it rains, therefore, it is not a reliable source of water during dry spells or extended droughts.
- Load-bearing slopes may deteriorate as a result of cistern leakage.
- Inadequate access protection can make cisterns and storage tanks dangerous for young children.